Russia's defence ministry has displayed a pair of drones that it said were captured following attacks on two Russian military bases in Syria.
President Vladimir Putin accused outside powers he refused to name of staging the incidents to derail a deal between Russia, Turkey and Iran that is intended to reduce hostilities in Syria.
Defence ministry officials said Saturday's raid on the Hemeimeem air base in the province of Lattakia and Russia's naval facility in the port of Tartus involved 13 drones.
It said seven were downed by air defence systems and the remaining six were forced to land by Russian electronic warfare units.
Of the latter, three exploded when they hit the ground and three more were captured intact, the ministry said.
The defence ministry presented two primitive-looking drones at a briefing, arguing they featured state-of-the art electronics that are less prone to jamming and allow precision strikes.
Major General Alexander Novikov, who heads the ministry's drone department, said the drones used in the weekend's raid differed from the rudimentary craft used earlier by rebels in Syria.
The attack required satellite navigation data that are not available on the internet, complex engineering works and elaborate tests, Mr Novikov said.
"The creation of drones of such class is impossible in makeshift conditions," Mr Novikov added.
"Their development and use requires the involvement of experts with special training in the countries that manufacture and use drones."
Mr Novikov did not blame any specific country but the defence ministry earlier referred to the "strange coincidence" of a US military intelligence plane allegedly barraging over the Mediterranean near the Russian bases when the attack took place.
The Pentagon strongly denied any involvement.
The defence ministry said the drones were launched from al-Mouazzara in Syria's north-western province of Idlib, more than 30 miles away from the Russian bases.
The attack heightened tensions between Russia and Turkey, which wields significant influence with some rebel groups in Idlib.
The province has become the main rallying point for various rebel factions after Syrian government forces won control over large swathes of territory thanks to Russian support.
Moscow has staunchly backed Syrian President Bashar Assad and Ankara has supported his foes, but they struck a deal last year to set up de-escalation zones.
The agreement has helped reduce fighting and improve ties between Russia and Turkey. It also involved Iran, another Assad backer.
Following the drone attack, the Russian defence ministry sent letters to Turkey's military leaders, asking them to deploy military observers to help prevent further attacks from Idlib on Russian assets.
Mr Putin said Moscow knows who helped stage the attack on the Russian bases but he did not identify the country allegedly involved, saying only that it was not Turkey.
He added that he discussed the raid with Turkish President Recep Tayyip Erdogan earlier on Thursday, voicing confidence that Turkey's leadership and military had nothing to do with it.
"There were provocateurs but they weren't the Turks," he said at a televised meeting with Russian newspaper editors on Thursday.
"We know who they were and how much they paid for that provocation."